ERIC Number: ED233023
Record Type: Non-Journal
Publication Date: 1978
Diurnal Variations in Maximal Oxygen Uptake.
McClellan, Powell D.
A study attempted to determine if diurnal (daily cyclical) variations were present during maximal exercise. The subjects' (30 female undergraduate physical education majors) oxygen consumption and heart rates were monitored while they walked on a treadmill on which the grade was raised every minute. Each subject was tested for maximal oxygen consumption on three different occasions. The times of day for testing periods were between 0800-0830, 1200-1230, and 1600-1630 hours. Data related to physical performances as measured by the total number of seconds subjects walked on the treadmill revealed significant differences between 0800 and 1200 and among 0800, 1200, and 1600. Significant increases in maximal oxygen consumption were noted between 0800 and 1200 and 0800 and 1600. The exact nature of this variation is unknown; however, an increased blood flow to the working muscles can be postulated. The results of this study imply the need for researchers to report the time at which tests for maximal performance are administered. Additionally, when maximal performances are being compared, subjects should be tested at the same time of day to reduce the variability due to diurnal variations. (JMK)
Publication Type: Reports - Research
Education Level: N/A
Authoring Institution: N/A